Selective delayed-action fuze



Fel 8, 1955 l.. P. GRANATH ET AL 2,701,527

SELECTIVE DELAYED-ACTION FUZE Filed July 6, 1948 2 Sheets-Sheet l ll III rNvENToR LOU/S l? G'/VATH SEL/M S PDIVOS ATTORNEY L. P. GRANATH ET A1. 2,701,527

SELECTIVE DELAYED-ACTION FuzE 2 Sheets-Sheet 2 FIG. 3

INVENTOR A LOU/5 E GN TH SEL/M s. Poo/Vas ATTORNEY Feb. 8, 1955 Filed July e. 194s SELECTIVE DELAYED-ACTION FUZE Louis P. Granath, Worcester, Mass., and Selim S. Podnos, Washington, D. C., assignors to the United States of America as represented by the Secretary of the Navy Application July 6, 1948, Serial No. 37,136

6 Claims. (Cl. 102-75) The present invention relates to a projectile fuze and more particularly to a selective delayed-action fuze of the percussion type designed for use in detonating high explosive projectiles.

An object of the invention is to provide an improved projectile fuze which will cause the detonation of the main bursting charge of the projectile to occur after complete penetration of the target, or, in the event of incomplete penetration of the target by the projectile, to occur at the maximum depth of penetration of the target.

Another object of the invention is to provide an improved projectile fuze which includes means to lock the firing mechanism in safety or unarmed position, the means being rendered inoperative when the projectile is in ight, and which is automatically armed at the moment of impact and then operates to detonate the primer of the fuze upon maximum penetration of the target.

A still further object of the invention is to provide an improved projectile fuze, simple in construction and having a minimum number of moving parts, whereby friction between adjoining parts is kept to a minimum, assuring a smooth and effective operation of the firing mechamsm.

Other objects of the invention will become apparent from the following description taken in connection with the accompanying drawings.

In one form of the invention the novel fuze includes a rebounding tiring mechanism, which is axially aligned with the direction of travel of the projectile in flight. The tiring mechanism is initially locked in safety or unarmed position by means of resiliently retained detents; while the projectile is in flight, centrifugal force is utilized to release the detents and unlock the reciproeable ring mechanism. Upon impact the tiring mechanism is initially projected forwardly to an armed position and, when the decelerating force has been reduced almost to zero, which occurs substantially at the end of the projectiles penetration, the plunger of the tiring mechanism is projected rearwardly by the expansion of a compressed spring to drive the firing pin into the primer.

In another form of the invention the rebounding action of the firing mechanism is dispensed with, and the energy of the initially compressed firing spring is utilized to thrust the firing pin rearwardly into the detonator or primer.

In both forms of the invention a one-way slideable arming sleeve and coacting locking balls are employed to initially restrain the plunger of the firing mechanism against accidental tiring action.

In the accompanying drawings:

Fig. 1 is a sectional view of a fuze mechanism according to this invention, showing the rebounding firing mechanism in unarmed or safety position;

Fig. 2 is a similar view with the firing mechanism in armed condition;

Fig. 3 is a similar view showing the mechanism in ring position; and

Fig. 4 is a sectional view of a modified form of fuze mechanism showing the firing mechanism in safety position.

In carrying out the invention a cylindrical housing, casing, or barrel 1 is provided to enclose the fuze mechanism, which includes an outer combined arming and guide sleeve 2 and an inner slide sleeve 3 in which the plunger of the tiring mechanism is contained. The plunger includes a preferably tubular stem 4 having an enlarged circular head 5 and tapered annular face 6, which terminates in the rng pin 7 that points to the rear of the projectile, as indicated in the drawings.

The tiring mechanism as a unit is longitudinally slideable in the outer casing or body 1 and the outer arming sleeve 2 of the tiring mechanism is retained in safety position by means of a suitable number of detents 8 which are radially mounted in radial seats or bores fashioned in the barrel 1. An annular exterior groove 9 is fashioned in the barrel 1 for the introduction of the series of radial detents, and to accommodate a coiled expansible spring 10 which surrounds the series of detents and resiliently retains them in operative position to prevent longitudinal movement of the outer sleeve 2.

The outer sleeve 2 is also fashioned with an exterior annular groove 11 in which is mounted a split expansible spring ring 12 and this spring ring is adapted to expand into an interior annular groove 13 fashioned with a shoulder in the bore of the barrel or casing 1 of the fuze. It will be understood that the arming sleeve 2 slides in one direction only, to arm the firing mechanism that is, to the left form the safety position of Figure 1 to thc position in Figures 2 and 3.

The firing plunger which is axially mounted within the fuze mechanism is supported by a coiled spring 14 which is interposed between a front end plate 15 and the head of the tiring plunger.

In safety position the firing plunger is locked against firing movement by an annular series of locking balls 16 which are fitted in apertures or sockets 17 in the inner :sleeve 3; these balls, as indicated, are clamped in the apertures by the tapered face: 6 of the plunger heid under pressure of the tiring spring 14. A rear plate 18 complementary to the front plate 15 retains the parts in safety or unarmed position, as indicated in Figure 1.

While the projectile is in flight, under centrifugal force the annular series of detents S is retracted from in front of the sleeve 2, against yielding pressure of the spring 10, in order that upon impact the sleeve 2 may slide forward with the sleeve 3 and the plunger.

In this arming movement, the expansible spring ring 12 snaps outwardly into the annular groove 13 to lock the outer sleeve 2 rigidly with the casing or barrel of the fuze, and thereafter this outer sleeve remains fixed relative to the outer casing.

Under force of impact and consequent forward movement of the plunger, the spring 14 is compressed by pressure from the head 5; the head also pushes against an annular shoulder 19, formed by an interior counterbore of the sleeve 3, thereby carrying the sleeve 3 with the plunger. In this forward movement the locking balls 16 in their sockets 17 move with the sleeve.

Substantially at the end of penetration of the target, that is, when the decelerating force caused by impact has diminished below the resilient force of the compressed spring, the plunger automatically rebounds to drive the ring pin 7 into the primer P to detonate the latter. A booster charge B may be provided as necessary.

In this rebounding movement the plunger, through the instrumentality of the locking balls 16, carries the slide sleeve 3 to the right in Figure 2, with the face 6 of the head 5 pushing against the balls 16. As the sockets 17 pass the rear annular edge of the locked sleeve 2 the balls are pushed outwardly and partially through their sockets into the annular space within the housing 1 at the rear of the locked arming sleeve 2. The plunger head 5, no longer restrained by the balls, plunges through the counterbore in the sleeve 3, to drive the pin 7 into the detonator or primer P.

It will be apparent that the rebounding firing unit, including the sleeve 3, the plunger, and the spring 14, which are rugged in construction and compact in arrangement, are not subject to breakage or accidental displacement. The parts are braced against lateral displacement, such as might occur upon contact with the ground or the surface of water; and, because of a minimum of frictional engagement of parts, they are free to perform their functions with facility and certainty.

In the modified form of the fuze mechanism, illustrated in Figure 4, the rebounding feature is absent, and the energy of the initially compressed spring 14 is utilized to plunge the pin 7 into the primer P.

The inner sleeve 3a, it will be noted, ts within the housing 1 and the opposite ends of the sleeve are closed by the front plate and the rear plate 18 of the fuze unit, the sleeve forming a stationary guide for the spring 14 and the plunger.

Under pressure of the spring 14 the tapered annular face 6a of the plunger head 5a tends to force the balls 16 outwardly, but the arming sleeve 2 holds the locking balls 16 within the sockets 17 to lock the plunger against accidental firing.

To unlock the plunger, the detents 8 are retracted under centrifugal force, and upon impact the arming sleeve 2 plunges forward, the spring ring 12 engaging shoulder 13 to retain the sleeve in armed position.

In its forward shift the arming sleeve releases the locking balls, thus permitting the tapered face 6a under action of the compressed spring 14 to push the balls outwardly from the path of the plunger. When the decelerating force, produced by impact of the projectile upon the target, has diminished below the resilient force of the compressed spring, the plunger, now freed of the restraining action of the balls 16, drives the firing pin 7 into the primer or detonator P.

While in both forms of the invention the firing action is accomplished by a rearward movement of the plunger, it will be understood that the fuze mechanisms herein described may be located in either the nose of the projectile or at the base thereof. The fuze, emboding the present invention, may be installed in various types of projectiles, including shells, rockets, bombs, etc., adapted for use against armor, concrete, wood, sand, earthworks or other similar targets that may be penetrated by the projectile. The word projectile as used in the appended claims is intended to include not only such missiles as are projected from cannons, guns, rocket launchers, etc., but bombs and the like. From the foregoing description it will be seen that we have provided simple, inexpensive and effective means for accomplishing all of the objects of the invention. It will be apparent that many changes may be made in the details of construction and arrangement of parts without departing from the spirit of the invention as expressed in the accompanying claims. We, therefore, do not wish to be limited to the exact details of construction and arrangement of parts shown and described as the preferred form only has been shown and described by way of illustration.

We claim:

l. In a fuze mechanism intended to be axially mounted on a projectile which rotates while in flight, a cylindrical housing having a series of apertures in the cylindrical wall adjacent to the forward end thereof, a guide sleeve axially slideable in the housing, safety detents positioned in said apertures and spring means forcing said detents into engagement with the end of said guide sleeve to restrain it against forward motion, said detents being retractable against the action of said spring means under the effects of centrifugal force thereby releasing the guide sleeve, coacting means on the housing and sleeve for retaining the latter in a forward position, said coacting means including an expansible spring ring, an inner sleeve having a counterbore in the rear end thereof and a series of transverse openings in said counterbore, said inner sleeve being axially slideable within said guide sleeve, a plunger in the inner sleeve, said plunger having on the rear end thereof an enlarged head terminating in a firing pin, the head being axially slideable in said counterbore, a detonator to the rear of and aligned with the ring pin, resilient means acting on said plunger and tending to drive such toward the detonator, and locking balls carried in the transverse openings in said inner sleeve coacting with the guide sleeve and plunger head to lock said plunger head to said inner sleeve for restraining said plunger head against rearward movement toward the detonator, said locking balls being releasable when the guide sleeve has slid forward in the housing upon impact of the projectile on the target and when said plunger and inner sleeve have rebounded upon deceleration of the projectile after impact, whereby the firing pin is free to be driven into the detonator by said resilient means.

2. In a fuze mechanism for use with a projectile which rotates in flight, a housing having an aperture adjacent to the forward end thereof, an arming sleeve forwardly slideable in the housing to arm the fuze, a safety detent positioned in said aperture and spring means forcing said detent into engagement with the end of said arming sleeve to restrain it against forward motion, said detent being retractable against the action of said spring means under the effects of centrifugal force thereby releasing the arming sleeve, coacting means on the housing and sleeve including an expansible spring ring for retaining the fuze in an armed condition after the sleeve has slid forward in the housing, a rebounding firing mechanism slideable in said arming sleeve, said firing mechanism comprising a slide sleeve having a counterbore in the rear end thereof and a transverse opening in the said counterbore, a plunger in the slide sleeve, said plunger having on the rear end thereof an enlarged head terminating in a firing pin, the head being axially slideable in said counterbore, a compressible spring within the slide sleeve for driving the firing pin rearwardly, and locking means including locking balls in the transverse opening in the slide sleeve coacting with the plunger head and arming sleeve to lock the plunger against rearward movement relative to said slide sleeve, said locking means being rendered inef fective after the arming sleeve has slid forward in the housing upon impact of the projectile on the target, by the rebounding action of the firing mechanism as the said compressible spring, compressed on impact of the projectile, expands upon deceleration of the projectile after impact, and a detonator to the rear of and aligned with the firing pin adapted to be detonated by said firing pin as the locking means are rendered ineffective upon the rebound of the firing mechanism.

3. In a fuze mechanism intended to be axially mounted on a projectile which rotates while in flight, a cylindrical housing having a series of apertures in the cylindrical wall adjacent to the forward end thereof, an arming sleeve axially slideable in the housing, safety detents positioned in said apertures and spring means forcing said detents into engagement with the end of said arming sleeve to restrain it against forward motion, said detents being retractable against the action of said spring means under the effects of centrifugal force thereby releasing the arming sleeve, coacting means on the housing and sleeve including an expansible spring ring for retaining the fuze in an armed condition after the sleeve has slid forward in the housing, a rebounding tiring mechanism slideable in said arming sleeve, said firing mechanism comprising a slide sleeve having a counterbore in the rear end thereof and an annular series of transverse openings in said counterbore, a plunger in the slide sleeve, said plunger having on the rear end thereof an enlarged head terminating in a firing pin, the head being axially slideable in said counterbore, a compressible spring within the slide sleeve exerting pressure upon the plunger for driving the firing pin rearwardly, and locking balls carried in the transverse openings in the slide sleeve coacting with the plunger head and arming sleeve to lock said plunger head to said slide sleeve for restraining the plunger against rearward motion, said locking balls being rendered ineffective, after the arming sleeve has slid forward in the housing upon impact of the projectile on the target, by the rebounding action of the firing mechanism as the said compressible spring, compressed on impact of the projectile, expands upon deceleration of the projectile after impact, and a detonator to the rear of and aligned with the firing pin, adapted to be detonated by said firing pin as the locking balls are rendered ineffective upon the rebound of the ring mechanism.

4. In a fuze mechanism for use with a projectile which rotates while in ight, a housing having a transverse aperture adjacent to the forward end thereof, an arming sleeve forwardly slideable in the housing to arm said mechanism, a safety detent positioned in said aperture and spring means forcing said detent into engagement with the end of the arming sleeve to restrain it against forward motion, said detent being retractable against the action of said spring means under the effects of centrifugal force thereby releasing the arming sleeve for forward motion, coacting means on the housing and sleeve for retaining the latter in a forward position, said coacting means including an expansible spring ring, an inner sleeve within said arming sleeve fixed relative to the housing and having a counterbore in the rear end thereof and a transverse opening in the counterbore, a plunger in the fixed inner sleeve, said plunger having on the rear end thereof an enlarged head terminating in a firing pin, said head being axially slideable in the coun terbore, a detonator to the rear of and aligned with the firing pin, a compressed spring positioned within the iixed sleeve and effecting pressure upon said plunger to drive such toward the detonator, and locking means in the transverse opening in the fixed sleeve coacting with the plunger head and arming sleeve to restrain the plunger against rearward motion toward the detonator, said locking means being releasable when the arming sleeve has slid forward in the housing upon impact of the projectile upon the target.

5. In a fuze mechanism intended to be axially mounted on a projectile which rotates while in flight, a cylindrical housing having a series of transverse apertures in the cylindrical wall adjacent to the forward end thereof, an arming sleeve axially slideable in the housing to arm said mechanism, safety detents positioned in said aper tures and spring means forcing said detents into engagement with the end of said arming sleeve to restrain it against forward motion, said detents being retractable against the action of said spring means under the effects of centrifugal force thereby freeing the arming sleeve for forward motion within the housing, coacting means on the housing and sleeve for retaining the fuze in an armed condition after the sleeve has slid forward, said coacting means including an expansible spring ring, an inner sleevc within said arming sleeve fixed relative to the housing and having a counterbore in the rear end thereof and an annular series of transverse openings in the counterbore, a plunger in the fixed inner sleeve, said plunger having on the rear end thereof an enlarged head terminating in a firing pin, said head being axially slideable in the counterbore, a detonator to the rear of and aligned with the firing pin, a compressed spring within the inner sleevc effecting pressure upon said plunger to forceably drive such toward the detonator, and locking balls in the transverse openings in the inner sleeve coacting with thc plunger head and arming sleeve to restrain the plunger against rearward motion toward the detonator, said locking balls being expellable from engagement with the plunger head when the arming sleeve has slid forward in the housing upon impact of the projectile upon the target.

6. In a fuze mechanism intended to be axially mounted on a projectile which rotates while in flight, a cylindrical housing being recessed at its forward end to define an annular shoulder, said housing having a plurality of transverse bores in its side wall adjacent the forward end, a cylindrical outer sleeve slidably contained within said housing, said outer sleeve having an annular groove in its outer wall proximate to the forward end thereof, an expansible spring ring compressed into said groove but releasable to engage said annular shoulder upon forward movement of said outer sleeve for retaining said outer sleeve in a forward position, a plurality of centrifugally releasable detents mounted in said bores to prevent the forward movement of said outer sleeve until centrifugal influences release said detents, a cylindrical inner sleeve having a counterbore in the rear end thereof and a plurality of transverse apertures adjacent the rear end thereof, said inner sleeve being slidably contained within said outer sleeve, a plunger in said inner sleeve, said plunger having on its rear end a circular head terminating in a ring pin, said head being axially slidable within said counterbore, a detonator to the rear of and opposing said firing pin, a spring urging said plunger rearwardly towards said detonator, and locking balls in the transverse apertures of said inner sleeve, said balls engaging said head to prevent rearward movement of said plunger relative to said inner sleeve until such time after impact of the projectile on the target when said outer sleeve has slid forward and said plunger and inner sleeve have rebounded under the urging of said spring upon deceleration of the projectile to release said locking balls and free said plunger to drive the firing pin into said detonator.

References Cited in the file of this patent UNITED STATES PATENTS 1,016,368 Schneider Feb. 6, 1912 1,549,763 Greenwell Aug. 18, 1925 2,378,626 Fanger June 19, 1945 2,441,897 Nichols May 18, 1948 

